US4922974A - Method of filling a liquid crystal device with liquid crystal - Google Patents

Method of filling a liquid crystal device with liquid crystal Download PDF

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Publication number
US4922974A
US4922974A US07/309,890 US30989089A US4922974A US 4922974 A US4922974 A US 4922974A US 30989089 A US30989089 A US 30989089A US 4922974 A US4922974 A US 4922974A
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United States
Prior art keywords
liquid crystal
crystal device
crystal material
blended
filling
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Expired - Fee Related
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US07/309,890
Inventor
Toshio Watanabe
Akio Osabe
Akira Mase
Hiroyuki Sakayori
Masahiko Sato
Kaoru Tabata
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Semiconductor Energy Laboratory Co Ltd
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Semiconductor Energy Laboratory Co Ltd
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Publication date
Priority claimed from JP7341387A external-priority patent/JPS63237027A/en
Priority claimed from JP7341487A external-priority patent/JPS63237028A/en
Application filed by Semiconductor Energy Laboratory Co Ltd filed Critical Semiconductor Energy Laboratory Co Ltd
Application granted granted Critical
Publication of US4922974A publication Critical patent/US4922974A/en
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1341—Filling or closing of cells

Definitions

  • This invention relates to a method of filling a liquid crystal device with a liquid crsytal.
  • Vacuum filling method is a known method for filling a space between a pair of substrates with a liquid crystal to manufacture a liquid crystal device.
  • the liquid crystal device is disposed together with the liquid crystal in a vaccum chamber at a vacuum, and then, after the inlet of the device is dipped in the liquid crystal, the pressure is elevated so that the liquid crystal enters the liquid crystal device.
  • This method is described in Japanese application No. sho 60-175192.
  • the inlet of the liquid crystal device is somewhat narrow so that the pressure in the liquid crystal device can not be lowered rapidly. Because of this, the liquid crystal device is subjected to the differential pressure between the inside and the outside of the liquid crystal device when the vacuum chamber is evacuated, and therefore tend to be deformed due to the undesirable pressure.
  • the filling process is generally carried out in a particular phase of liquid crystal.
  • a ferroelectric liquid crystal exhibits its phase transition as the temperatue varies, e.g. Cry phase ⁇ Smc phase ⁇ SmA phase ⁇ Iso phase. The phase transition is observed also with a blended liquid crystal.
  • An Iso (isotropic) phase is suitable for the filling process because of its low viscousity.
  • An example of the method is described in Japanese Patent Application No. sho60-175192.
  • FIG. 1 is a schematic view showing a method of filling a liquid crystal device with a liquid crystal in accordance with the present invention.
  • FIG. 2 is a schematic view showing another method of filling a liquid crystal device with a liquid crystal in accordance with the present invention.
  • FIGS. 3(A), 3(B) and 3(C) are explanatory views showing the distance between parallel substates of a liquid crystal device, in which measured points are given marks x and the measurement results are written below the marks.
  • the liquid crytal device comprises a pair of glass substrates which are firmly arranged in parallel and spaced a certain distance to produce a space therebetween.
  • a liquid crystal device 1 is placed in a vacuum chamber 3 whose pressure is maintained at 1 ⁇ 10 -4 Torr or higher by a vacuum pump 7 while the liquid crystal device 1 is heated by a heater 2.
  • a dispenser 4 accommodating a liquid crystal therein is heated by a heater 5 above the transition temperature so that the liquid crystal is maintained in the Iso phase.
  • the liquid crystal is a blended liquid crystal composed of two or more constituent liquid crystals. An amount of the liquid crystal is poured to the inlet of the liquid crystal device. In this process, the temperature of the liquid crystal is always maintained higher than the transition temperature of any constituent liquid crystal by the heaters 2, 4 and 6.
  • nitrogen gas is introduced at 20 SCCM to the inside of the vacuum chamber 3 to produce a differential pressure between the outside and the inside of the liquid crystal device whereupon the liquid crystal in Iso phase is forced to enter the device under the pressure.
  • the pressure in the chamber is eventually elevated to an atmospheric pressure.
  • FIG. 2 is a schematic view showing a second embodiment of a method in accordance with the present invention.
  • the liquid crystal device 1 comprising a pair of substrates with spacers inbetween is disposed between parallel plates 8 and 9 of a press 12.
  • the attitudes of the plates are precisely adjusted in parallel.
  • the liquid crystal device is pressed in the vertical direction by means of the parallel plates 8 and 9 at 1 Kg/cm 2 .
  • the pressure should be determined in accordance with the evacuation level, e.g. 0.5-5.0 Kg/cm 2 .
  • FIGS. 3(A), 3(B) and 3(C) are explanatory views in which measured points are given marks x and the measurement results are written below the marks in micrometers.
  • FIG. 3(A) shows the result of measurement prior to filling.
  • FIG. 3(B) shows the result after filling in accordance with prior art. As shown in the figure, the disparity of distance was enlarged by the prior art filling process.
  • FIG. 3(C) shows the result after filling in accordance with the present invention. With the precise experimental measurements, there was no appliciable change between after and before the filling process.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)

Abstract

A method of filling a liquid crystal device with a blended liquid crystal material is set forth. The liquid crystal device is filled by disposing the liquid crystal device having an inlet port, in a vacuum chamber, evacuating the vacuum chamber, supplying the inlet port with the blended liquid crystal material, and elevating the pressure in the chamber to allow the blended liquid crystal material to fill the liquid crystal device through the inlet port by virtue of the differential pressure between the inside and the outside of the liquid crystal device, with the temperature of the blended liquid crystal material being maintained, until the liquid crystal device is completely filled with the blended liquid crystal material, at a temperature higher than the transition temperature of any one of the constituents of the blended liquid crystal material so that the blended liquid crystal material is transformed in its isotropic phase.

Description

This is a divisional application of Ser. No. 07/174,401 filed Mar. 25, 1988.
BACKGROUND OF THE INVENTION
This invention relates to a method of filling a liquid crystal device with a liquid crsytal.
Vacuum filling method is a known method for filling a space between a pair of substrates with a liquid crystal to manufacture a liquid crystal device. In this prior art method, the liquid crystal device is disposed together with the liquid crystal in a vaccum chamber at a vacuum, and then, after the inlet of the device is dipped in the liquid crystal, the pressure is elevated so that the liquid crystal enters the liquid crystal device. One type of this method is described in Japanese application No. sho 60-175192.
However, there are several shortcomings associated with this method. The inlet of the liquid crystal device is somewhat narrow so that the pressure in the liquid crystal device can not be lowered rapidly. Because of this, the liquid crystal device is subjected to the differential pressure between the inside and the outside of the liquid crystal device when the vacuum chamber is evacuated, and therefore tend to be deformed due to the undesirable pressure.
To comply with the shortcoming, it is proposed to mate a pair of substrates firmly to bear the differential pressure and maintain the distance between substrates with two or more types of spacers arranged therein. Nevertheless, in some instances the device may be destroyed due to a transient force of about 1 kg/cm2 which arises during evacuation.
Furthermore, the filling process is generally carried out in a particular phase of liquid crystal. A ferroelectric liquid crystal exhibits its phase transition as the temperatue varies, e.g. Cry phase ←→ Smc phase ←→ SmA phase ←→ Iso phase. The phase transition is observed also with a blended liquid crystal. An Iso (isotropic) phase is suitable for the filling process because of its low viscousity. An example of the method is described in Japanese Patent Application No. sho60-175192.
However, when a blended liquid crystal material composed of several constituent liquid crystals is used, a particular liquid crystal of the constituents tends to enter first so that the liquid crystal material having entered into the device becomes different from the prescribed composition. Having carefully investigated the phenomena, the inventors found that the transition temperature of the blended liquid crystal is not observed clear at a certain defenite temperature and a mixed phase seems to appear between the constituents due to differential transition temperatures of the constituent liquid crystals. In other word, it may happen during filling process that a constituent liquid crystal is of Iso phase while another constituent liquid crystal remains in Smc phase.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a method of filling a liquid crystal device with liquid crystal.
It is another object of the invention to provide a method of filling a liquid crystal device with liquid crystal in which the yield of product is not lowered due to the process.
It is a further object of the invention to provide a method of filling a liquid crystal device with liquid crystal without deforming the device by the filling process.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing a method of filling a liquid crystal device with a liquid crystal in accordance with the present invention.
FIG. 2 is a schematic view showing another method of filling a liquid crystal device with a liquid crystal in accordance with the present invention.
FIGS. 3(A), 3(B) and 3(C) are explanatory views showing the distance between parallel substates of a liquid crystal device, in which measured points are given marks x and the measurement results are written below the marks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a method of filling a liquid crystal device with a liquid crystal in accordance with the present invention will be explained. The liquid crytal device comprises a pair of glass substrates which are firmly arranged in parallel and spaced a certain distance to produce a space therebetween.
In FIG. 1, a liquid crystal device 1 is placed in a vacuum chamber 3 whose pressure is maintained at 1×10-4 Torr or higher by a vacuum pump 7 while the liquid crystal device 1 is heated by a heater 2. On the other hand, a dispenser 4 accommodating a liquid crystal therein is heated by a heater 5 above the transition temperature so that the liquid crystal is maintained in the Iso phase. The liquid crystal is a blended liquid crystal composed of two or more constituent liquid crystals. An amount of the liquid crystal is poured to the inlet of the liquid crystal device. In this process, the temperature of the liquid crystal is always maintained higher than the transition temperature of any constituent liquid crystal by the heaters 2, 4 and 6.
Then, nitrogen gas is introduced at 20 SCCM to the inside of the vacuum chamber 3 to produce a differential pressure between the outside and the inside of the liquid crystal device whereupon the liquid crystal in Iso phase is forced to enter the device under the pressure. The pressure in the chamber is eventually elevated to an atmospheric pressure.
FIG. 2 is a schematic view showing a second embodiment of a method in accordance with the present invention.
In FIG. 2, like numbers are given to corresponding parts to the first embodiment and the redundant explanation is dispensed with. The liquid crystal device 1 comprising a pair of substrates with spacers inbetween is disposed between parallel plates 8 and 9 of a press 12. The attitudes of the plates are precisely adjusted in parallel. During filling of liquid crystal, the liquid crystal device is pressed in the vertical direction by means of the parallel plates 8 and 9 at 1 Kg/cm2. The pressure should be determined in accordance with the evacuation level, e.g. 0.5-5.0 Kg/cm2.
After filling the liquid crystal device with liquid crystal, the distance between the substrates of the device was measured at several points. FIGS. 3(A), 3(B) and 3(C) are explanatory views in which measured points are given marks x and the measurement results are written below the marks in micrometers. FIG. 3(A) shows the result of mesurement prior to filling. FIG. 3(B) shows the result after filling in accordance with prior art. As shown in the figure, the disparity of distance was enlarged by the prior art filling process. FIG. 3(C) shows the result after filling in accordance with the present invention. With the precise experimental measurements, there was no appliciable change between after and before the filling process.
While a description has been made for several embodiments, the present invention should be limited only by the appended claims and should not be limited by the particualr examles. What follow are some examples of modifications and variation according to the invention.

Claims (1)

We claim:
1. A method of filling a liquid crystal device with a blended crystal material comprising:
disposing said liquid crystal device having an inlet port, in a vacuum chamber;
evacuating said vacuum chamber;
supplying said inlet port with said blended liquid crystal material; and
elevating the pressure in said chamber to allow said blended liquid crystal material to fill said liquid crystal device through said inlet port by virtue of the differential pressure between the inside and the outside of said liquid crystal device,
wherein said blended liquid crystal material is maintained, until said liquid crystal device is completely filled with said blended liquid crystal material, at a temperature higher than the transition temperature of any one of the constituents of said blended liquid crystal material so that said blended liquid crystal material is transformed in its isotropic phase.
US07/309,890 1987-03-26 1989-02-14 Method of filling a liquid crystal device with liquid crystal Expired - Fee Related US4922974A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP62-73413 1987-03-26
JP7341387A JPS63237027A (en) 1987-03-26 1987-03-26 Injection into liquid crystal cell
JP7341487A JPS63237028A (en) 1987-03-26 1987-03-26 Injection of liquid crystal having ferroelectricity
JP62-73414 1987-03-26

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5024255A (en) * 1987-07-27 1991-06-18 Semiconductor Energy Laboratory Co., Ltd. Method of filling a liquid crystal device with ferroelectric liquid crystal material
US5141036A (en) * 1987-07-27 1992-08-25 Semiconductor Energy Laboratory Co., Ltd. Method of filling a liquid crystal device with introduction of liquid crystal by increasing pressure
US5246042A (en) * 1991-09-24 1993-09-21 Litton Systems Canada Limited Method of filling a suspended particle display
US20040149379A1 (en) * 2000-10-30 2004-08-05 Takeshi Kobayashi Adjusting apparatus of gap width and method thereof
US20060149388A1 (en) * 2004-12-30 2006-07-06 Smith Todd S Orthopaedic bearing and method for making the same

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3911359A1 (en) * 1989-04-07 1990-10-11 Nokia Unterhaltungselektronik METHOD FOR FILLING A LIQUID CRYSTAL CELL
JP2808478B2 (en) * 1990-05-23 1998-10-08 キヤノン株式会社 Method and apparatus for manufacturing liquid crystal panel
JPH04218018A (en) * 1990-06-14 1992-08-07 Hoechst Japan Ltd Manufacture of liquid crystal cells
US5137484A (en) * 1991-06-13 1992-08-11 Proxima Corporation Method of making a liquid crystal display construction
US5241995A (en) * 1991-09-24 1993-09-07 Litton Systems Canada Limited Method of filling a suspended particle display
US5507323A (en) * 1993-10-12 1996-04-16 Fujitsu Limited Method and dispenser for filling liquid crystal into LCD cell
CA2108237C (en) * 1993-10-12 1999-09-07 Taizo Abe Method and dispenser for filling liquid crystal into lcd cell

Citations (10)

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Publication number Priority date Publication date Assignee Title
US3701368A (en) * 1971-06-23 1972-10-31 Rca Corp Fabrication of liquid crystal devices
JPS527015A (en) * 1975-07-08 1977-01-19 Nippon Kogaku Kk <Nikon> Fluid replenishing method
US4064919A (en) * 1976-11-22 1977-12-27 Rca Corporation Method of filling dynamic scattering liquid crystal devices
US4091847A (en) * 1976-11-22 1978-05-30 Rca Corporation Process for filling dynamic scattering liquid crystal cells
US4098301A (en) * 1976-12-23 1978-07-04 Rca Corporation Method to provide homogeneous liquid crystal cells containing a dyestuff
JPS56168633A (en) * 1980-05-30 1981-12-24 Sharp Corp Liquid crystal display element
JPS56168627A (en) * 1980-05-29 1981-12-24 Alps Electric Co Ltd Manufacture of liquid crystal display device
US4626303A (en) * 1982-10-27 1986-12-02 Canon Kabushiki Kaisha Process for making electro-optic element
JPS6234129A (en) * 1985-08-08 1987-02-14 Semiconductor Energy Lab Co Ltd Manufacture of liquid crystal device
US4753276A (en) * 1987-05-19 1988-06-28 Central Glass Company, Limited Method and apparatus for injecting liquid into display device cell

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3701368A (en) * 1971-06-23 1972-10-31 Rca Corp Fabrication of liquid crystal devices
JPS527015A (en) * 1975-07-08 1977-01-19 Nippon Kogaku Kk <Nikon> Fluid replenishing method
US4064919A (en) * 1976-11-22 1977-12-27 Rca Corporation Method of filling dynamic scattering liquid crystal devices
US4091847A (en) * 1976-11-22 1978-05-30 Rca Corporation Process for filling dynamic scattering liquid crystal cells
US4098301A (en) * 1976-12-23 1978-07-04 Rca Corporation Method to provide homogeneous liquid crystal cells containing a dyestuff
JPS56168627A (en) * 1980-05-29 1981-12-24 Alps Electric Co Ltd Manufacture of liquid crystal display device
JPS56168633A (en) * 1980-05-30 1981-12-24 Sharp Corp Liquid crystal display element
US4626303A (en) * 1982-10-27 1986-12-02 Canon Kabushiki Kaisha Process for making electro-optic element
JPS6234129A (en) * 1985-08-08 1987-02-14 Semiconductor Energy Lab Co Ltd Manufacture of liquid crystal device
US4753276A (en) * 1987-05-19 1988-06-28 Central Glass Company, Limited Method and apparatus for injecting liquid into display device cell

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5024255A (en) * 1987-07-27 1991-06-18 Semiconductor Energy Laboratory Co., Ltd. Method of filling a liquid crystal device with ferroelectric liquid crystal material
US5141036A (en) * 1987-07-27 1992-08-25 Semiconductor Energy Laboratory Co., Ltd. Method of filling a liquid crystal device with introduction of liquid crystal by increasing pressure
US5246042A (en) * 1991-09-24 1993-09-21 Litton Systems Canada Limited Method of filling a suspended particle display
US20040149379A1 (en) * 2000-10-30 2004-08-05 Takeshi Kobayashi Adjusting apparatus of gap width and method thereof
US7527083B2 (en) 2000-10-30 2009-05-05 Au Optronics Corporation Apparatus for adjusting gap width of laminated body
US20090221208A1 (en) * 2000-10-30 2009-09-03 Takeshi Kobayashi Adjusting Apparatus of Gap Width and Method Thereof
US20060149388A1 (en) * 2004-12-30 2006-07-06 Smith Todd S Orthopaedic bearing and method for making the same

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